Expansion valve



Dec; 14 1926.

F. C. BELL EXPANSION VALVE Filed Jan. 24 1924 INVENTORS. FRED. C. BELL.

L uMl-MF ATTOR N EYS Patented Dec. 1%, 1926.

NT STA neiatsa FRED C. BELL, 0F ALAMEDA, CALIFORNIA.

EXPANSION VALVE.

Application filed January 24. 1924. Serial No. 688,152.

The object of the present invention is to generally improve and simplify the construction andoperation of valves of the character described; to provide positive stops for limiting movement of the diaphragm, thereby preventing excess movement and straining thereof; to provide a structure which permits perfect alignment of the valve with relation to its seat, and quick and ready removal of the valve for inspection, regrinding and otherwise; and further, to provide a diaphragm and a valve actuated thereby, which are sensitive to the slightest variation in adjustment so that practically any pressure may be obtained and maintained with precision. One form which my invention may assume is exemplified in the following description and illustrated in the accompanying drawings, in which Fig. 1 is a central, vertical, longitudinal section of the valve.

Fig. 2 is an enlarged cross-section on line 2--2 Fig. 1. i

Fig. 3 is a plan view of the diaphragm cover.

Referring to the drawings in detail, and particularly to Fig. 1, A indicates a cylindrical shaped elon ated casting, in one end of which is formed a cylinder chamber 2.

Formed on each side of the cylindrical el0n gated casting, as shown in Fig. 2, are projecting bosses 3 and 4. These bosses are drilled and tapped to receive pipes not here shown, the boss 4 serving as an inlet connection, and the boss 3 as a discharge.

Forming a continuation of the drilled and tapped passage in the boss 4, and extending to a point substantially central of the casting A, is a passage 5. and drilled downwardly from the cylinder chamber 2 to a point where it will intercept the passage 5 is a valve seat and passage 6. The passages 6 and 5 theret0re communicate with the inlet connection, while a passage 7, shown in dotted lines in Fig. 1, and in full linesin Fig. 2, serves as a discharge or outlet passage as passage 7 is drilled through from the cylinder chamber 2 to appoint where it intercepts the drilled and tapped passage in the boss 3. lln fact, the passage 7 is drilled completely through the casting A and as such also communicates with a chamber 8 formed in the opposite "end of the casting, which will hereinafter be referred to as the diaphragm chamber. The casting is enlarged at this end by an annular disk-like flange 9, the peripheral portion of which is flanged and internally threaded as at 10 to receive a cover member B.

A flexible diaphragm 11 is interposed between the cover and the chamber 8 and is secured by the cover. It forms a closure for r the chamber 8 and as a gasket is interposed between the diaphragm and the body, a sealed connection is obtained. The cylinder chamber is also closed by a cover member such as shown at 12, and the function thereof will later be described.

The cover B is provided with a central guide 13. in which is mounted a tension spring 14, this spring being interposed between two buttons such as indicated at 15 and 16, the button. 15 engaging the dia phragm, while the button 16 is engaged-b an adjusting screw 17 which extends through the cover, said screw being set when adjusted by a lock-nut18. The opposite side of the diaphragm is also engaged by a button such as shown at 19, which is positioned in the diaphragm chamber. This button is provided with a central guide pin 20, which extends into a centrally drilled passage provid 'dr-illed passages 21 and 22 formed in the casting A and they thus enter the cylinder chamber 2. A valve guide 23 is slidably mounted in this chamber and is secured to the outer ends of the yoke pins 21 and 22; that is. the valve guide is drilled to receive the outer ends of the yoke pins and as such may be removed in unison with the same; for instance, if it is desired to dissemble the valve for inspection, repair. cleaning or otherwise, or for the purpose of removing the valve when regrinding the same.

' Theivalve guide is also centrally drilled for the reception of a valve such as indicated at 24. This valve engages the seat 6 and it is held against this seat by means of a spring 25 interposed between the cover 12 and the valve. A second or auxiliaryspring 26 is also employed, this spring being interposed between the cover 12 and the valve guide and it serves the function of moving Hill the valve guide in unison with the yoke pins 21 and 22, the button 19 and the diaphragm, as will hereinafter be described.

The valve here illustrated may be used in numerous installations, but for the purpose of illustration it might be stated that it is employed as an expansion valve in a refrigcrating plant. If this is the case we will assume that liquid, such as ammonia or the like, is delivered to the inlet connection 3 at a pressure of approximately 180 pounds, and further that it is desired to maintain a pressure in the expansion and cooling coils of the plant at approximately 25 pounds. In this case it can be readily seen that if the pressure in the cooling coil is less. than the required pressure, for instance 25 pounds, spring 14 will have depressed the diaphragm and the movement of the diaphragm will have been communicated to the valve, thus opening it and allowing the liquid to pass and enter the cylinder chamber or, in other words, the space 28 formed between the valve guide and the bottom of the cylinder chamber. A gas is formed the moment the liquid is permitted to expand and this gas discharges downwardly through'the port or passage 7 and thus discharges through the outlet 3 or the pipe connected therewith. The gas will continue escaping until a pressure is built up which approximates 25 pounds. This pressure is exerted on the diaphragm 11 as the passage 7 is also in communication with the diaphragm chamber 8. The spring 14 has previously been set to a pressure of 25 pounds and when this pressure is reached or exceeded, diaphragm 11 will move in the d rection of: arrows The valve guide 23 which bears on the ends of the yoke pins 21 and 22, due to the pressure of the springs 25 and 26, will now follow the diaphragm as the button 19 engages the same and valve 24 will therefore be brought intoengagement with its seat, thus temporarily, at least, stopping any further inflow of liquid under pressure. The moment, however, the pressure drops to the slightest degree, diaphragm 11 again flexes or moves and valve 24 slightly opens, thus admitting further liquid and permitting expansion thereof to maintain the pressure at the point desired. The valve is thus automatic in operation and will continue to function as long as the ammonia orother li uid employed is supplied and is maint-aine at substantially the pressure specified.

The tension of the s ring 25 is just sufficient to retain the va ve on its seat when subjected to the pressure specified. The

pressure exerted by this spring is, of course, greater than that actually required to insure a positive seating of the valve, but any great excess pressure should not be exerted as it might have a tendency to score or cut the valve or the seat, for instance, if

particles of scale, grit or the like, should accidentally interpose themselves between the members. Such excess pressure is avoided by the use of the auxiliary spring 26, this spring serving two functions, first that of retaining the valve guide 23 in positive engagement with the outer ends of the yoke pins and with a sufficient excess pressure to insure movement of the valve guide in unison with the yoke pins when the diaphragm operates; that is, it sometimes happens that the yoke pins or the valve guide proper become slightly gummed by oil or otherwise and might therefore have a tendency to stick or bind, but this is not the case in the present instance as the tension of the spring 26 is sufficient to overcome any such resistance. Spring 26 also serves another function,'to-wit, that of partially counteracting the tension of the spring 14. This is also of considerable importance as it permits a more sensitive adjustment of the screw 17 and the spring and diaphragm actuated thereby.

The structure here shown permits perfect accessibility and removal of the Working parts.

It should be remembered that the valve indicated at 24 requires constant attention as it is often necessary to regrind the same as leaka'ge would otherwise occur. Accessibility to the valve is here readily obtained as it is only necessary to. remove the cap 12. It is also important that the valve be maintained in positive alignment with its seat. This is obtained by employing the valve guide indicated at 23. It'is also important that movement be positively and synchronously transmittedto the valve guide and the valve when the diaphragm flexes. This is taken care of in a simple manner by the use of the button 19 and the yoke pins 21 and 22. It is furthermore important that the movement of the diaphragm be limited in both directions as unnecessary flexing and straining thereof inight otherwise take place. This is taken care of by placing a number of radially disposed ribs 30 in the cap B. The upper ends of these ribs are disposed on a sli ht incline so as to form a seat for the diap ragm when it flexes in the direction of arrows a, and movement in the opposite direction is limited by the inner surface of the disk like flange 9 which is similarly flared as indicated at 9*: All features, such as accessibility, perfect alignment of the valve and valve guide, and simpl city of construction, "are taken care of. Perfect control and operation are maintained and as this is the case it is obvious that it may be employed in numerous installations.

lVhile certain features of the present in vention are more or less specifically illustrated, I wish it understood that various changes in form and proportion may be reprising a casting having a chamber formed at one end. which is closed by a spring adjusted diaphragm, said casting also having a cylinder chamber formed in its opposite end, a yoke member actuated by the 21::

and having legs entering the cylinder-chamber, a slidable valve guide in the cylinder chamber actuated by the legs, a valve carried by the guideeand adapted to regulate an inflow of fluid through an inlet port formed in the casting, said valve being slidable independently of the valve guide and a spring engaging the valve.

2. A valve of the character described com prising a casting having a chamber formed at one end, which is closed by a spring adjusted diaphragm, said casting a cylinder chamber formed in its opposite end, a yoke member phragm and having legs entering the cylinder chamber, a slidable valve guide in the cylinder chamber actuated by the legs, a valve carried by the guide and adapted to regulate an inflow of fluid through an inlet port formed in the casting, said valve being slidable independently of the valve guide, a-

cover forming a closure for the cylinder chamber, and a pair of sprin s in the cylinder chamber, one interposed between the cover and valve guide, and the other interposed between the cover and the valve.

In a valve of the character described, a cylindrical shaped, elongated casting having a central solid portion and a cylinder chamher, and a diaphragm chber formed at the also having actuated by the din opposite end, a spring actuated diaphra forming a closure for the diaphragm chamher, a button mounted in said chberengaging the diaphragm a pair of pins engaged by the button and extending through guideways formed in the central solid portion' of the casting, said pins extending into the cylinder chamber, a slidable valve guide in the cylinder chamber ened by the pins,

and a valve slidably mounted in the valve guide and adapted to regulate an ion of a flni under pressure through an inlet formed in the casting.

i. m a valve of e character described, a cylindrical shaped elongated casting having a central solid portioma cylinder chamber and a diaphra chamber formed therein at the respective opposite ends, a spring-actuated diaphragm forming aclosure for the diaphragm" chber, a button mounted in such chamber and engaging the diaphra, a pin on the button and forming a de' for the button, said central solid portion having a guide passage formed therein for recepti n of the guide pin on the button, said solid portion also having a pair oiide rm formed therein one on each side of the a pair of pins slidably named guide passage, mounted in said last-named gu de passages, a slidable valve de mounted in the cylin der chamber, said valve guide being engaged by one end of the pins and the other end of the pin being engaged by the button, a valve slidably mounted in the valve guide and adapted to regulate an inflow of fluid under pressure through an inlet formed in tbfe solid portion of the casting, a cap' forg a closure for the cylinder chamber, springs in the cylinder chamber one engaging the valve and the other engaging the valve guide, said second-named spr main taining the valve de in engagement with the pair ofpins.

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